Stone Calculator for Massachusetts Trench, Pad and Drain Volumes

The order that comes up short is almost always a trench. Someone measures thirty feet of French drain, enters thirty in the length box, and forgets that the number the stone calculator needs is a volume: thirty feet long by the trench width by the trench depth, all three. Stone for a pad is forgiving of a small error because it spreads out. Stone for a trench is not, because a trench half full is a trench that has to be finished with a second delivery, and it is where a wet Massachusetts spring finds the weak spot.

Four ways a graded stone order comes out wrong

Length instead of volume. A 24-foot drain 18 inches wide and 14 inches deep is 36 square feet of trench bottom, not 24 of anything. Width and depth in a trench are usually the smaller numbers and always the ones people round down.

One depth for a two-layer job. A drive is a compacted base with a surface course on it. Entering the finished thickness once, with one material selected, gives a number that is wrong for both layers. Run them separately.

The pipe. A 4-inch pipe occupies barely a tenth of a cubic yard over a thirty-foot run, which is less than a wheelbarrow. Deducting it looks careful and simply leaves you short at the outfall.

Switching grade after calculating. The yardage will not move when you change from #57 to screenings, but the tonnage will, because the two are published at different weights. If you change your mind about the material, press calculate again.

A trench, a pad and a splash strip in one session

Choose rectangle, circle or multiple areas, up to five. Enter length and width in feet, or a diameter for a circle. Depth goes in as inches, from 0.25 to 24, which is enough for a French drain at a foot deep but not for a two-foot retaining-wall backfill in one pass. Split anything deeper into two runs and add them.

Select the material so the right weight is applied. Leave the optional 5% for compaction and spillage ticked if you want that margin built in. Press calculate and cubic yards, tons and cubic feet come back together, with an email field if you want the estimate sent to you.

For a trench, the length and width belong to the trench, not to the lawn it crosses. For a pad, they are the pad itself. It is worth walking a drain run with a tape before typing anything, since trenches wander wider than they were dug to.

1.40 tons a yard for #57, 1.45 once you switch to screenings

The arithmetic is short. Square feet times depth in inches divided by 12 gives cubic feet. Divide by 27 for cubic yards. Multiply yards by the material weight for tons.

The weights this site publishes sit in a narrow band and still change an order. Most graded crushed stone, #57 and #67 and 3/4 inch and the 3/8 inch chips, is about 2,800 lb per cubic yard, or 1.40 tons. Stone Dust and the #4 and ballast sizes are a little heavier at about 2,900 lb, or 1.45. Crusher run and processed gravel are about 3,000 lb, or 1.50, because the fines fill the spaces. Rip rap is heaviest at about 3,100 lb, or 1.55.

Worth knowing in your head: a ton of #57 spread 4 inches deep covers roughly 58 square feet, and about 77 square feet at 3 inches. If the calculator and that estimate are far apart, the depth box is where to look.

Washed stone or stone with fines, and where gravel takes over

The catalog splits into two families and the split decides whether water moves.

Washed grades such as #57 Stone, #67 Stone and 3/4 inch crushed stone have open space between the pieces, which is what makes them drainage stone. Put fines in a French drain and the drain stops working, which on ground that already holds snowmelt near the surface is an expensive mistake to bury.

Materials with fines, crusher run and processed gravel and stone dust, lock up under a plate and make a firm layer. Stone dust is the New England default under flagstone and pavers, laid as a thin screeded bed over a compacted base rather than as the base itself.

Two boundaries save wasted orders. Grade numbers get smaller as the stone gets bigger, so #4 is 3/4 to 1-1/2 inch material, #57 is 3/16 to 1 inch, #67 is a quarter to three quarters, and #89 runs from 3/8 down into fines. And this page handles graded stone: surface material for a drive, walkway gravel and pea stone belong on the gravel calculator, because they are sized to be walked and driven on rather than specified by grade.

A 24-foot drain, a shed pad and a construction entrance

Hypothetical jobs, arithmetic shown.

French drain, 24 ft by 18 in wide by 14 in deep. The trench bottom is 24 x 1.5 = 36 sq ft. Then 36 x 14 / 12 = 42 cu ft, 42 / 27 = 1.56 cu yd, and 1.56 x 1.40 = 2.18 tons of #57. Line the trench with non-woven fabric before the stone goes in.

Shed pad top course, 10 by 14 ft at 4 inches. 140 sq ft, so 140 x 4 / 12 = 46.7 cu ft, 46.7 / 27 = 1.73 cu yd, 1.73 x 1.40 = 2.42 tons.

Construction entrance in #4, 30 by 12 ft at 6 inches. 360 sq ft, 360 x 6 / 12 = 180 cu ft, 180 / 27 = 6.67 cu yd. At the 1.45 tons per yard published for the #4 and ballast sizes, that is 9.67 tons. Run the same volume as #57 instead and it reads 9.33.

Angular clean stone settles roughly 5 to 10% under traffic, so on a driven surface the 5% tick is doing real work. Round up as well: arranging a half-ton top-up afterwards is rarely worth anyone's time.

Once the tonnage looks right, open the product page for the grade you selected, set quantity and a delivery date, and check out. Delivery is arranged at checkout by ZIP code, and the load needs somewhere firm with clear access to go down.

Common questions

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